The present invention relates to a method for the preparation of non-woven fabric containing polyvinyl alcohol fiber (PVA fiber), and particularly to a method for preparation of non-woven fabric in which scarcely soluble PVA fiber, which is soluble or swellable in the presence of water at the temperature of 90.degree. C. or higher, is utilized as fibrous binder.
In general two types of PVA fiber are provided, that is, so called soluble PVA fiber which is soluble in water at the temperature of 50.degree. to 80.degree. C. and scarcely soluble PVA fiber which is insoluble or soluble in water only at the temperature of 90.degree. C. or higher. The soluble PVA fiber is dissolved by hot water treatment or steam treatment to exhibit adhesiveness, but on the other hand the scarcely soluble PVA fibers will not be dissolved by these treatments and does not exhibit adhesiveness. Therefore the soluble PVA fiber has been used conventionally to prepare non-woven fabrics which contain PVA fiber as fibrous binder. However non-woven fabrics formed by hot water treating and drying webs comprising soluble PVA fiber and other fibers, such as synthetic fibers and regenerated fibers blended in given proportions, lack softness and exhibit a paper-like feeling. This disadvantage results from the behavior of soluble PVA fiber in bonding that the fiber is dissolved and forms a film-like structure to bond fibers to each other. If the amount of soluble PVA fiber is decreased to obtain softness, the resulting non-woven fabric lacks strength. Furthermore, because soluble PVA fiber is dissolved in water at temperatures as low as 50.degree. to 80.degree. C., when the fiber is subjected to wet heat-treatment, such as a hot water treament, the fiber swells considerably, the strength of the fiber is decreased, and the obtained fabrics lack in water resistivity. Thus these fabrics find limited application.